Currently, 3GPP has set up a new project called Narrowband Internet of Things (NB-IoT). An objective of this project is to further extend a current Long Term Evolution (LTE) system, so as to support massive low-throughput Internet of Things devices or massive Internet of Things devices insensitive to a delay requirement. Ultra-low complexity and ultra-low power consumption are two key requirements for such Internet of Things devices.
Terminal devices in conventional LTE systems and Internet of Things devices in NB-IoT are collectively referred to as user equipment (UE). The UE is usually in an idle mode when no service requires transmission. When there is a service requiring data transmission, the UE changes into a connected mode from the idle mode.
Each time when the UE connects to a network because there is data that may need to be transmitted/received, the UE may need to perform massive procedures of message exchange with network-side devices, so as to receive downlink data or transmit uplink data. The network-side devices mainly include a base station such as an evolved NodeB (eNB), and core network devices such as a mobility management entity (MME) and a serving gateway (SGW). A main objective of the massive message exchange is still to establish a connection between the UE and the eNB and establish a valid access stratum context. Therefore, to reduce the massive message exchange performed each lime when the UE connects to a network, currently, the 3GPP organization agrees to save access stratum context information (referred to as context information below), and in particular, to save some UE-specific access stratum parameters, on a UE side and an eNB side, so as to reduce radio resource control (RRC) signaling overheads. This helps quickly connect to the network based on the context information saved in the UE and the eNB, to resume data transmission.
However, currently when the context information of the UE is saved in the UE and the eNB, and in particular, when the UE has downlink data that may need to be received, the UE usually triggers, based on a received paging message, a data transmission resumption processing process. Therefore, how UE receives a paging message to further reduce UE power consumption is a problem to be resolved.
Currently, UE usually receives a paging message in the following manner: A paging frame (PF) and a paging occasion (PO) that are for receiving a paging message first may need to be calculated. Specifically, one paging occasion may be one subframe. One paging frame may include a plurality of paging subframes. A PF and a PO are calculated based on the following formulas.
A PF is derived by using the following formula. A system frame number (SFN) that makes the following formula true is obtained:SFN mod T=(T div N)*(UE_ID mod N).
For a PO, i_s is first derived from the following formula, and then a corresponding PO value is obtained based on the obtained i_s and a radio access technology of the UE by searching the following table:
i_s=floor(UE_ID/N) mod Ns, where
T is a DRX interval of the UE;
nB is selected from 4T, 2T, T, T/2, T/4, T/8, T/16, and T/32;
N=min(T,nB);
Ns=max(1,nB/T); and
UE_ID=IMSI mod 1024.
Generally, radio access technologies for UE include frequency division duplex (FDD) and time division duplex (TDD).
FDD:PO whenPO whenPO whenPO whenNsi_s = 0i_s = 1i_s = 2i_s = 319N/AN/AN/A249N/AN/A40459
TDD (all UL/DL configurations):PO whenPO whenPO whenPO whenNsi_s = 0i_s = 1i_s = 2i_s = 310N/AN/AN/A205N/AN/A40156
After the PF and the PO are determined, the UE decodes a physical downlink control channel (PDCCH) at the determined PO time point by using a paging radio network temporary identifier (P-RNTI), and then receives a paging message from a physical downlink shared channel (PDSCH) based on a resource indicated by the PDCCH. When the received paging message includes identification information of the UE, the UE determines itself as paged UE, and connects to the network as instructed by the network.
It can be learned, from the manner of receiving the paging message, that after the UE decodes the PDCCH at the PO time point and further receives the paging message from the PDSCH, the paging message may not include the identification information of the UE. In this case, this is false paging for the UE. For UE in NB-IoT or other UE sensitive to power consumption, excessive false paging leads to a relatively high waste of power consumption during paging message detection. Therefore, for UE sensitive to power consumption, the current paging mechanism is apt to cause wasting of power consumption of the UE.